Absorbent rate, softness, and strength are key properties for a facial tissue. The absorbent rate of a facial tissue affects its performance in capturing sneezes and nose blows. If the absorbent rate is too slow the contents of the exudate may be wiped across the face or transferred to other surfaces. In general, softness and strength are inversely related such that a reduction in strength will produce an increase in softness. There are practical limits to softness improvements from strength reduction before the tissue becomes too weak to use.
Softness can be enhanced by the topical addition of softening agents, such as a silicone emulsion, to the outer surfaces of the fibrous web. However, softening agents and post treatment steps can be expensive, increase manufacturing complexity, and can reduce the absorbent rate and strength of the tissue.
An alternative to surface treatments is the use of creping and creping chemistries to increase tissue softness. One such alternative is described, for example, in U.S. Pat. No. 7,883,604, which discloses increasing tissue softness by creping with a water insoluble dispersion that modifies the surface of the tissue web with a thin, discontinuous polyolefin film. Unfortunately the water insoluble nature of the polyolefin dispersion may negatively impact tissue machine runability and require removal from a mill's waste water system.
An alternative to water insoluble dispersions is described in US Publication No. 2010/0155004, which discloses a water soluble creping chemistry comprising a film forming component and a modifier component. Although these water soluble creping chemistries eliminate many of the tissue machine's operational challenges, their use still requires a removal step to prevent accumulation of the water soluble chemicals in the mill's water system.
As such, a need currently exists for a creping composition that produces a soft tissue, but is also retained on the sheet so as not to negatively impact manufacturing efficiency or require additional waste water treatment.